In liquid supply pipes widely used in industrial facilities, such as a pipeline of a ship, a pipe of a sewage sludge treatment facility, an internal pipe of a construction plant facility, and a beverage supply pipe in beverage equipment such as used for beer, foreign matters such as scale, germs, etc. are deposited on an inner wall surface thereof due to properties of the liquid contained therein and environmental factors at sites where the facilities are installed.
Specifically, when various types of liquids such as food and beverages flow in the conduit for a long period of time, corrosion occurs on an inner surface of the conduit. Corrosion refers to a phenomenon in which metal contacts with a surrounding liquid or gas to chemically or electrochemically react therewith, thereby causing damage. Another definition for the corrosion may be described as the following phenomenon in which:                A) a change occurs in a conduit carrying water due to external physical effects;        B) a substance which is not chemically stable comes into contact with any substance to cause an electrical change, and a chemical change occurs in that region;        C) every substance has its own electric potential, and when a substance having a different electric potential approaches a substance having such electric potential, a magnetic reaction occurs to form foreign matters; and        D) oxygen acts on a substance to cause a change (oxidation).        
Meanwhile, in a comprehensive sense, the corrosion may be defined as a phenomenon in which a material is deteriorated due to the environment.
Further, slime referred to as so-called fur is deposited on the inner surface of the conduit. The slime deposited on the inner surface of the conduit as described above not only spoils the flavor of a liquid for drinking, but also becomes a site where germs, etc. may grow, thereby causing a contamination of the corresponding liquid.
In particular, in a general water pipe, slime is generated in a form of a scale deposited due to the corrosion in the conduit, and scale is deposited in another form of slime in a conduit for drawing food and beverages.
Meanwhile, as disclosed in Korean Patent Registration No. 10-0588047, conventionally, there has been an attempt to remove the slime such as scale by injecting a slime removing agent into the conduit or by injecting high-pressure washing water.
However, the conventional method of removing slime has problems of not only decreasing a removal efficiency, but also leading to harmful results to a human body due to a chemical composition contained in the agent when using the slime removing agent, and causing environmental pollution.